Fix T70276: View animation with jpeg 2000 image will crash player

Since our ffmpeg is built with openjpeg support and thus can decode jpeg
2000 (in both J2K and JP2 codec flavors as well as high bitdepths), added
these extensions to the supported list.

Also IMB_ispic > IMB_ispic_type > imb_is_a_jp2 was only testing for jp2,
now do both jp2/j2k.

Reviewers: brecht

Maniphest Tasks: T70276

Differential Revision: https://developer.blender.org/D5909

source/blender/imbuf/intern/jp2.c

@@ -83,7 +83,7 @@ static OPJ_CODEC_FORMAT format_from_header(const unsigned char mem[JP2_FILEHEADE
 
 int imb_is_a_jp2(const unsigned char *buf)
 {
-  return check_jp2(buf);
+  return (check_jp2(buf) || check_j2k(buf));
 }
 
 /**

source/blender/imbuf/intern/util.c

@@ -252,6 +252,8 @@ static int isffmpeg(const char *filename)
   if (BLI_path_extension_check_n(filename,
                                  ".swf",
                                  ".jpg",
+                                 ".jp2",
+                                 ".j2c",
                                  ".png",
                                  ".dds",
                                  ".tga",